Fault indicator for closed circuit installations



Nov. 22; 1949 J. GIORGIANNI 2,488,622

FAULT INDICATOR FOR CLOSED CIRCUIT INSTALLATIONS Filed Oct. 25, 1946 MAIN L/NE g I J /5 EA'LAY TO ALAEM AME/W PO/NT INVENTOR.

Patented Nov. 22, 1949 sTAT-Eis: oF-FlcE FAUL'll. INDICATOR .FOR,CLQSEDiCIRGULI. INSTALLATlQNS.

Joseph Giorgianni, Providence; m1: Application October 25, 1946, SerialNo. 705.559.

ZiGlfiilflSa. (Cl. 177-311) The present invention relates to normallyclosed c ircuit installations such -as burglar alarinu syste-msandthelike, and has specific reference toan indicatorfor detecting andlocalizing-defectsinthe lineand the-- installation parts.

The principal object of the invention is :to provi'd'eaz positiveindicator which localizes the dee feet, and I thus'permits-quick"repairs to bemadei Another object of the invention is to provide alocalizing indicator which operates only when an open or an intermittentbreak occurs in a closed circuit system, and remains in indicatingposition until released manually.

With the above and other objects and advantageous features in view, theinvention consists of a novel arrangement of parts more fully disclosedin the detailed description following, in conjunction with theaccompanying drawings, and more specifically defined in the claimsappended thereto.

In the drawings:

Fig. 1 is a diagrammatic view of a portion of a normally closed electriccircuit having a local alarm point, a novel indicator being included fordisclosing a local break;

Fig. 2 is a plan view of the face of an electric meter which is modifiedto lock the needle in place after registering a circuit break; and

Fig. 3 is a detail on the line 3-3 of Fig. 1 showing a preferredarrangement for exerting a locking action on the meter needle.

It has been found desirable to provide a positive indication of a localbreak in a normally closed circuit installation, such as is commonlyused for burglar alarms and the like. These systems usually have aseries of local alarm points, such as windows, doors and other openings,and it often happens that one or more Of the local points is disturbedsufficiently by local atmospheric conditions to break the circuit andthus set off the alarm. However, since there is no actual visible break,an exhaustive search is required to find out where the disturbance orbreak occurred, and complete re-wiring is frequently necessary, as thetrouble often corrects itself before the investigation and the check upare made. A closed circuit burglar alarm system of standard type, forexample, includes a relay for controlling the alarm, the relay normallyreceiving a constant flow of current from the source of supply, whichflows through a number of separate alarm points through switches, lines,and tinfoil back to the source of supply. When a pronounced break occursat any alarm point the difficulty thusbecomes neicfissarytocheckeachalarm point;

circuit;

Ihave; found'fitifeasible to .connectanindicator ff he. lt'aletyp acrosseach. alarm, pointinstallation, the' preferred" indicator being afl'ash" bulb. When an intermittent break occurs within any of theinstallations, the current passes through the flash bulb at thatinstallation. which cannot carry the line current and therefore burnsout. The particular defective installation is thus positivelyidentified, and repair of the break is rapid, as no other installationneed be tested.

Referring to the drawings, the line If), H is conveyed through an alarmpoint or installation by connections l2, l3 and M, the alarm point beingin series with an alarm relay in the usual manner, to provide a normallyclosed electric circuit which operates the alarm whenever the circuit isbroken. I have connected an indicator IS in parallel with the alarmpoint, whereby it normally receives insuflicient current for registeringbut receives full line current if the circuit at the alarm point becomesbroken. The indicator 15, which preferably is a flash bulb, then burnsout, and thus positively indicates the local installation where thecurrent was broken. Instead of a flash bulb, any similar positiveindicator which normally is not operated when placed in parallel with alocal alarm point circuit, may be used, such as for example, a visibletype fuse or a relay or circuit breaker.

For certain local installations a voltmeter or ammeter may be placed inthe alarm point circuit, the parts being so arranged that when a breakoccurs and causes the meter needle to move, the needle is releasablyretained in moved position until manually released, thus givin apositive indication which localizes the break.

One preferred manner of register-locking a meter needle in place isshown in Figs. 2 and 3, wherein the meter I6 is provided with the usualindicating needle l1, and a tension wire I8 is fastened at one end l9 tothe meter face, and is connected to a coil spring 20, the outer end ofwhich is also fastened to the meter face as indicated at 2|, whereby thewire l8 extends across the path of travel of the needle in frictionalcontact therewith. The tension of the wire I8 on the needle is adjustedso that the needle will move when a break in the closed circuit at thecan be visually located, but a minor break caused alarm point occurs,but will be frictionally held 3 so as not to swing back to its initialposition until the wire I8 is manually lifted or its tension otherwisereleased sufficiently to permit the needle to swing to its originalindication for the normally closed circuit.

It is thus clear that I have provided an indicator for visuallydisclosing a break in a local alarm point installation, which isphysically changed, as by burning out or by moving, whenever a breakoccurs in the normally closed electrical circuit of the installation.

Although I have described specific constructional arrangements forpositively indicating a local break in a normally closed electricalcircuit, it is obvious that other arrangements for obtaining the desiredindication may be utilized, within the spirit and the scope of theinvention as defined in the appended claims.

I claim:

1. In an alarm apparatus, in combination, a current source, wiringincluding alarm sections in a normally closed circuit, an alarm, a relayin series with the normally closed alarm section circult and operable onopening of the circuit of an alarm section to actuate the alarm, and aninz.

dicator in parallel with each alarm section, said indicator beingunaffected by the normally closed circuit and physically effected uponbreaking of its alarm section circuit by passage of full circuittherethrough.

2. In an alarm apparatus, in combination, a current source, wiringincluding alarm sections in a normally closed circuit, an alarm, a relayin series with the normally closed alarm section circuit and operable onopening of the circuit of an alarm section to actuate the alarm, and anindicator in parallel with each alarm section, said indicator beingunaffected by the normally closed circuit and physically efi'ected uponbreaking of its alarm section circuit by passage of full circuittherethrough, said indicator including an indicating fuse.

JOSEPH GIORGIANNI.

REFERENCES CITED The following references are of record in the tile ofthis patent:

UNITED STATES PATENTS Number Name Date 378,078 Barnes Feb. 21, 1888659,499 Ullman Oct. 9, 1900 1,158,146 Olney Oct. 26, 1915 1,927,370Kriegstedt Jan. 12, 1932 2,159,751 saul May 23, 1939 2,279,394 FountainApr. 14, 1942

